Đáp án+Giải thích các bước giải:
`3) sqrt{4+sqrt7}`
`=sqrt2.sqrt{4+sqrt7}:sqrt2`
`=sqrt{8+2sqrt7}:sqrt2`
`=sqrt{7+2sqrt7+1}:sqrt2`
`=sqrt{(sqrt7+1)^2}:sqrt2`
`=|sqrt7+1|:sqrt2`
`=(sqrt7+1)/sqrt2`
`=((sqrt7+1).sqrt2)/(sqrt2.sqrt2)`
`=(sqrt14+sqrt2)/2`
`4) sqrt{6-3sqrt3}+sqrt{2-sqrt3}`
`=sqrt{2.3-3.sqrt3}+sqrt{2-sqrt3}`
`=sqrt3.sqrt{2-sqrt3}+sqrt{2-sqrt3}`
`=(sqrt3+1)(sqrt{2-sqrt3})`
